The present invention relates generally to doors and mechanisms for moving doors relative to a door frame defining an access opening.
Most doors are mounted in door frames by two or more hinges along one side edge for swinging (pivotal) movement about a vertical axis between closed and open positions relative to an access opening in the door frame. For doors associated with buildings, the swing arc is only limited by the wall surface surrounding or adjacent to the door frame such that the door usually can be opened so as to expose the entire access opening. However, vehicle door assemblies typically have a swing arc that is limited to less than 90° such that the door access opening is not completely exposed when the door is “fully” open. This limited space makes it difficult for a person having less than complete mobility to ingress and egress the vehicle.
Instead of swinging movement, sometimes it is desirable to mount a door on tracks for sliding movement generally parallel to a plane of the door access opening. For example, many vehicles such as panel trucks and vans have at least one side door mounted for sliding movement along an outer side surface of the vehicle. Such a door is typically slidably connected to an upper track located at an upper edge of the door frame access opening near the vehicle roof, a lower track located at a lower edge of the door frame access opening near the sill area, and a center track located in the vehicle side wall near a rear edge of the door frame access opening. This sliding mechanism permits movement of the door a short distance outwardly from the door access opening and then generally parallel to the plane of the door access opening. Although such a configuration can be used with vehicles having generally planar sides such as panel trucks, conversion vans and mini vans, it is not well suited for passenger cars, station wagons and car-based SUV's.